<!DOCTYPE html>
<html>
    <head>
    <meta charset="utf-8" name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
    <title></title>
    </head>
    <body>	
        <h1 id="a">Hello world</h1>
        <script src="tw.js"></script>
        <script>
        const demo = new TW();

        demo.twget('a')
        .clear()
        .tw("哈哈哈哈哈")
        .clear();

        </script>
    </body>
</html>